The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

GG marriage stance 'influential': Greens

Governor-General Quentin Bryce's open support for same-sex marriage will be hugely influential across all voter groups, Greens Senator Sarah Hanson-Young says.

Ms Bryce said during a lecture in Sydney on Friday she hoped for Australia to become a nation where "people are free to love and marry whom they choose".

At a marriage equality rally in Melbourne on Saturday, Ms Hanson-Young said the comment represented the desires and the aspirations of Australians to have a fair, decent country.

"(The governor-general) is using her position to speak and give voice to the aspirations of many Australians," Ms Hanson-Young said.

"Australia is falling behind.

"To have the governor-general step forward and say this is something Australians care about, and as the governor-general, she believes that marriage equality is a human right ... it's hugely influential across all voter groups.

Ms Hanson-Young rejected criticism Ms Bryce had attracted for her comments, saying it was an issue that should be above politics.